1. Estimate the objective overall rate of CR (CR+CRi) for age-adjusted HiDAC (age <60 years: 2 gm/m2 IV Q12hours days 1-5; age >60 years: 1.5 gm/m2 IV Q12hours days 1-5) followed by pembrolizumab 200 mg IV on day 14 in relapsed and refractory AML patients